A heat advisory is in effect until 7 p.m. Wednesday across a large part of the state, the National Weather Service said early Tuesday morning.

Forecasters expect temperatures in the upper 90s and low 100s with high humidity and heat indexes of 105 to just more than 110 degrees, the weather service said.

The heat-index values will exceed 105 by late morning, forecasters said, and continue through the early evening.

The counties included in the advisory are: Arkansas; Bradley; Calhoun; Clark; Cleburne; Cleveland; Conway; Dallas; Desha; Drew; Faulkner; Garland; Grant; Hot Spring; Jefferson; Johnson; Lincoln; Logan; Lonoke; Monroe; Montgomery; Ouachita; Perry; Pike; Polk; Prairie; Pulaski; Saline; Scott; Van Buren; White; Woodruff and Yell.

The high heat indexes make heat-related illness more likely, the weather service said, so precautions are advised, including wearing light-weight clothing, taking frequent breaks when working outside and drinking plenty of water.